diff --git a/docs/user/interface/Size.dox b/docs/user/interface/Size.dox
index e20ebf5dc9..897882d507 100644
--- a/docs/user/interface/Size.dox
+++ b/docs/user/interface/Size.dox
@@ -22,7 +22,8 @@
 /*!
 	\var B_SIZE_UNSET
 
-	A meaningless size value.
+	A placeholder size value. Controls that are passed this value
+	will create their own sizing.
 
 	\since Haiku R1
 */